black under toenails

I had a major back surgery in December and still can't bend well and am not supposed to. Well, in the tub tonight I was able to reach my toes and decided the polish really needed to come off and they were getting a tad long. It has been four months since surgery.
When I got the polish off I was shocked to see black stuff under the nail (just the part you can clean, not the actual nail bed). Was this a fungus from not being able to dry my feet well b/c of not bending? I have never had this before so I am kinda at a loss. I was able to get 90% off by cutting the nail short, but what I couldn't cut didn't come off with the metal nail file to clean under the nail or my nail brush. Any ideas what this is?
Thanks!

I had a major back surgery in December and still can't bend well and am not supposed to. Well, in the tub tonight I was able to reach my toes and decided the polish really needed to come off and they were getting a tad long. It has been four months since surgery.
When I got the polish off I was shocked to see black stuff under the nail (just the part you can clean, not the actual nail bed). Was this a fungus from not being able to dry my feet well b/c of not bending? I have never had this before so I am kinda at a loss. I was able to get 90% off by cutting the nail short, but what I couldn't cut didn't come off with the metal nail file to clean under the nail or my nail brush. Any ideas what this is?
Thanks!

It could just be blood from a hematoma, or it could be a pseudomonas bacterial infection. If ALL the black came off when you scraped it and the nail appeared normal, then you can possibly rule out infection. Pseudomonas will generally turn the nail plate from green to brown to black, but will also cause the nail to separate from the nail bed and will have no apparent debris to 'scrape' out. I could also just be from poor circulation from the surgery, or from being 'laid up' for so long. If you are concerned, ask your physician the next time you go in for a check up. I would advise not wearing polish until it is all cleared up, or until after you see your doctor.

well, it isn't still under all the nails, but is under one or two-but not in the nail bed. I had my ingrown nails removed (all four borders) last year, and just since surgery (when the big toe nails finally were able to GROW), all my toenails are much longer than ever before, especially not being able to file them or anything due to not being able to really reach them (so I can't "clean" them with a file hardly).
I am not worried. I didn't have my nails colored for about a month to two months after surgery, and they were fine then, but like I said, about 1/2 a month ago when the polish came off, there was that black stuff. I kinda thought it was from moisture getting caught under the nail, but heck, I don't have a clue!! Never has happened before, and I have had five major surgeries.
Anyway, thanks for your input. If I see my doc anytime soon, and it is still there then I will ask.